[TenTec] Noise from Fans

[Bill NY9H]

how many fans / how many amps...
are you limited to current capacity of the lm317 , or does that drive 
some of the transistors????


At 12:37 PM 3/7/2014, you wrote:
>Guys,
>
>I've designed a small circuit that will run the a dc fan at high 
>speed for a dozen seconds then drop the speed down to as low as it will run.
>
>That way, the fan is sure to start, no matter how much cat hair it's 
>sucked up, or the condition of the bearings. Once started, runs at 
>full speed for a bit,  then it slows downs.
>
>both the fast on and slow run speeds are adjustable.
>
>input voltage may be either 6.3 v ac, 12 v ac, or 12-18 v dc.
>
>The prototype pcbs should be here within a week or so.
>
>The circuit is simple, four transistors, a LM317 and a few diodes.
>
>
>Mike, WB8VGE
>SunLight Energy Systems
>The Heathkit Shop
>http://www.theheathkitshop.com/
>J e e p
>o|||||||o
>
>A man with one clock knows what time it is. A man with two clocks is 
>never sure.
>
>
>
>On Mar 7, 2014, at 12:16 PM, Rick - DJ0IP / NJ0IP <Rick at DJ0IP.de> wrote:
>
> > A few diodes would be cheaper than lots of beer.
> > You don't even have to calculate much.
> > Just figure on 0.6v drop per resistor.
> > I buy these diodes generally 100 at a time.
> > They cost just a few pennies each in those quantities.
> >
>
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